RUBY-891 Rename Standalone topology to Single and add tests

lib/mongo/cluster.rb

@@ -34,7 +34,7 @@ class Cluster
     # @return [ Object ] The cluster topology.
     attr_reader :topology
 
-    def_delegators :topology, :replica_set?, :replica_set_name, :sharded?, :standalone?, :unknown?
+    def_delegators :topology, :replica_set?, :replica_set_name, :sharded?, :single?, :unknown?
 
     # Determine if this cluster of servers is equal to another object. Checks the
     # servers currently in the cluster, not what was configured.

lib/mongo/cluster/topology.rb

@@ -14,7 +14,7 @@
 
 require 'mongo/cluster/topology/replica_set'
 require 'mongo/cluster/topology/sharded'
-require 'mongo/cluster/topology/standalone'
+require 'mongo/cluster/topology/single'
 require 'mongo/cluster/topology/unknown'
 
 module Mongo
@@ -32,17 +32,18 @@ module Topology
       OPTIONS = {
         replica_set: ReplicaSet,
         sharded: Sharded,
-        direct: Standalone
+        direct: Single
       }
 
       # Get the initial cluster topology for the provided options.
       #
       # @example Get the initial cluster topology.
       #   Topology.initial(topology: :replica_set)
       #
+      # @param [ Array<String> ] seeds The addresses of the configured servers.
       # @param [ Hash ] options The cluster options.
       #
-      # @return [ ReplicaSet, Sharded, Standalone ] The topology.
+      # @return [ ReplicaSet, Sharded, Single ] The topology.
       #
       # @since 2.0.0
       def initial(seeds, options)
@@ -52,7 +53,7 @@ def initial(seeds, options)
         if options.has_key?(:replica_set)
           ReplicaSet.new(options)
         else
-          seeds.size > 1 ? Unknown.new(options) : Standalone.new(options)
+          seeds.size > 1 ? Unknown.new(options) : Single.new(options)
         end
       end
     end

lib/mongo/cluster/topology/replica_set.rb

@@ -135,15 +135,15 @@ def servers(servers)
         # @since 2.0.0
         def sharded?; false; end
 
-        # A replica set topology is not standalone.
+        # A replica set topology is not single.
         #
-        # @example Is the topology standalone?
-        #   ReplicaSet.standalone?
+        # @example Is the topology single?
+        #   ReplicaSet.single?
         #
         # @return [ false ] Always false.
         #
         # @since 2.0.0
-        def standalone?; false; end
+        def single?; false; end
 
         # A replica set topology is not unknown.
         #

lib/mongo/cluster/topology/sharded.rb

@@ -107,15 +107,15 @@ def servers(servers)
         # @since 2.0.0
         def sharded?; true; end
 
-        # A sharded topology is not standalone.
+        # A sharded topology is not single.
         #
-        # @example Is the topology standalone?
-        #   Sharded.standalone?
+        # @example Is the topology single?
+        #   Sharded.single?
         #
         # @return [ false ] Always false.
         #
         # @since 2.0.0
-        def standalone?; false; end
+        def single?; false; end
 
         # A sharded topology is not unknown.
         #

lib/mongo/cluster/topology/standalone.rb → lib/mongo/cluster/topology/single.rb

@@ -16,20 +16,20 @@ module Mongo
   class Cluster
     module Topology
 
-      # Defines behaviour for when a cluster is in standalone topology.
+      # Defines behaviour for when a cluster is in single topology.
       #
       # @since 2.0.0
-      class Standalone
+      class Single
 
         # The display name for the topology.
         #
         # @since 2.0.0
-        NAME = 'Standalone'.freeze
+        NAME = 'Single'.freeze
 
         # Get the display name.
         #
         # @example Get the display name.
-        #   Standalone.display_name
+        #   Single.display_name
         #
         # @return [ String ] The display name.
         #
@@ -48,13 +48,13 @@ def display_name
         # @param [ Array<Server> ] servers The list of known servers to the
         #   cluster.
         #
-        # @return [ Standalone ] The topology.
+        # @return [ Single ] The topology.
         def elect_primary(description, servers); self; end
 
         # Initialize the topology with the options.
         #
         # @example Initialize the topology.
-        #   Standalone.new(options)
+        #   Single.new(options)
         #
         # @param [ Hash ] options The options.
         #
@@ -63,20 +63,20 @@ def initialize(options)
           @options = options
         end
 
-        # A standalone topology is not a replica set.
+        # A single topology is not a replica set.
         #
         # @example Is the topology a replica set?
-        #   Sharded.replica_set?
+        #   Single.replica_set?
         #
         # @return [ false ] Always false.
         #
         # @since 2.0.0
         def replica_set?; false; end
 
-        # Standalone topologies have no replica set name.
+        # Single topologies have no replica set name.
         #
         # @example Get the replica set name.
-        #   standalone.replica_set_name
+        #   single.replica_set_name
         #
         # @return [ nil ] Always nil.
         #
@@ -86,41 +86,43 @@ def replica_set_name; nil; end
         # Select appropriate servers for this topology.
         #
         # @example Select the servers.
-        #   Standalone.servers(servers, 'test')
+        #   Single.servers(servers, 'test')
         #
         # @param [ Array<Server> ] servers The known servers.
         #
-        # @return [ Array<Server> ] The standalone servers.
+        # @return [ Array<Server> ] The single servers.
         #
         # @since 2.0.0
         def servers(servers, name = nil)
-          [ servers.detect{ |server| server.standalone? } ]
+          [ servers.detect do |server|
+              !server.unknown? && !server.arbiter? && !server.ghost?
+            end ]
         end
 
-        # A standalone topology is not sharded.
+        # A single topology is not sharded.
         #
         # @example Is the topology sharded?
-        #   Standalone.sharded?
+        #   Single.sharded?
         #
         # @return [ false ] Always false.
         #
         # @since 2.0.0
         def sharded?; false; end
 
-        # A standalone topology is standalone.
+        # A single topology is single.
         #
-        # @example Is the topology standalone?
-        #   Standalone.standalone?
+        # @example Is the topology single?
+        #   Single.single?
         #
         # @return [ true ] Always true.
         #
         # @since 2.0.0
-        def standalone?; true; end
+        def single?; true; end
 
-        # An standalone topology is not unknown.
+        # An single topology is not unknown.
         #
         # @example Is the topology unknown?
-        #   Standalone.unknown?
+        #   Single.unknown?
         #
         # @return [ false ] Always false.
         #

lib/mongo/cluster/topology/unknown.rb

@@ -118,15 +118,15 @@ def servers(servers)
         # @since 2.0.0
         def sharded?; false; end
 
-        # An unknown topology is not standalone.
+        # An unknown topology is not single.
         #
-        # @example Is the topology standalone?
-        #   Unknown.standalone?
+        # @example Is the topology single?
+        #   Unknown.single?
         #
         # @return [ true ] Always false.
         #
         # @since 2.0.0
-        def standalone?; false; end
+        def single?; false; end
 
         # An unknown topology is unknown.
         #

lib/mongo/server_selector/selectable.rb

@@ -86,7 +86,7 @@ def initialize(tag_sets = [], options = {})
       def select_server(cluster)
         deadline = Time.now + server_selection_timeout
         while (deadline - Time.now) > 0
-          if cluster.standalone?
+          if cluster.single?
             servers = cluster.servers
           elsif cluster.sharded?
             servers = near_servers(cluster.servers)
@@ -136,7 +136,7 @@ def local_threshold
       # @since 2.0.0
       def primary(candidates)
         candidates.select do |server|
-          server.primary? || server.standalone?
+          server.primary?
         end
       end
 

spec/mongo/cluster/topology/replica_set_spec.rb

@@ -92,10 +92,10 @@
     end
   end
 
-  describe '.standalone?' do
+  describe '.single?' do
 
     it 'returns false' do
-      expect(described_class.new({})).to_not be_standalone
+      expect(described_class.new({})).to_not be_single
     end
   end
 end

spec/mongo/cluster/topology/sharded_spec.rb

@@ -65,10 +65,10 @@
     end
   end
 
-  describe '.standalone?' do
+  describe '.single?' do
 
     it 'returns false' do
-      expect(topology).to_not be_standalone
+      expect(topology).to_not be_single
     end
   end
 end

spec/mongo/cluster/topology/standalone_spec.rb → spec/mongo/cluster/topology/single_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe Mongo::Cluster::Topology::Standalone do
+describe Mongo::Cluster::Topology::Single do
 
   let(:address) do
     Mongo::Address.new('127.0.0.1:27017')
@@ -70,10 +70,10 @@
     end
   end
 
-  describe '.standalone?' do
+  describe '.single?' do
 
     it 'returns true' do
-      expect(topology).to be_standalone
+      expect(topology).to be_single
     end
   end
 end

spec/mongo/cluster/topology_spec.rb

@@ -15,14 +15,14 @@
       end
     end
 
-    context 'when provided a standalone option' do
+    context 'when provided a single option' do
 
       let(:topology) do
         described_class.initial([ 'a' ], connect: :direct)
       end
 
-      it 'returns a standalone topology' do
-        expect(topology).to be_a(Mongo::Cluster::Topology::Standalone)
+      it 'returns a single topology' do
+        expect(topology).to be_a(Mongo::Cluster::Topology::Single)
       end
     end
 
@@ -56,8 +56,30 @@
           described_class.initial([], {})
         end
 
-        it 'returns a standalone topology' do
-          expect(topology).to be_a(Mongo::Cluster::Topology::Standalone)
+        it 'returns a single topology' do
+          expect(topology).to be_a(Mongo::Cluster::Topology::Single)
+        end
+      end
+
+      context 'when provided a single mongos', if: single_mongos? do
+
+        let(:topology) do
+          described_class.initial(ADDRESSES, {})
+        end
+
+        it 'returns a single topology' do
+          expect(topology).to be_a(Mongo::Cluster::Topology::Single)
+        end
+      end
+
+      context 'when provided a single replica set member', if: single_rs_member? do
+
+        let(:topology) do
+          described_class.initial(ADDRESSES, {})
+        end
+
+        it 'returns a single topology' do
+          expect(topology).to be_a(Mongo::Cluster::Topology::Single)
         end
       end
     end

spec/mongo/cluster_spec.rb

@@ -126,4 +126,28 @@
       expect(cluster.scan!).to be true
     end
   end
+
+  describe '#servers' do
+
+    context 'when topology is single', if: single_seed? do
+
+      let(:cluster) do
+        described_class.new(ADDRESSES)
+      end
+
+      context 'when the server is a mongos', if: single_mongos?  do
+
+        it 'returns the mongos' do
+          expect(cluster.servers.size).to eq(1)
+        end
+      end
+
+      context 'when the server is a replica set member', if: single_rs_member? do
+
+        it 'returns the replica set member' do
+          expect(cluster.servers.size).to eq(1)
+        end
+      end
+    end
+  end
 end

spec/mongo/database_spec.rb

@@ -158,7 +158,7 @@
     context 'when an alternate read preference is specified' do
 
       before do
-        allow(database.cluster).to receive(:standalone?).and_return(false)
+        allow(database.cluster).to receive(:single?).and_return(false)
       end
 
       let(:read) do

spec/mongo/server_selection_spec.rb

@@ -17,7 +17,7 @@
       let(:cluster) do
         double('cluster').tap do |c|
           allow(c).to receive(:topology).and_return(topology)
-          allow(c).to receive(:standalone?).and_return(topology.standalone?)
+          allow(c).to receive(:single?).and_return(topology.single?)
           allow(c).to receive(:sharded?).and_return(topology.sharded?)
           allow(c).to receive(:replica_set?).and_return(topology.replica_set?)
         end